Comcast has been letting me test-drive its new "X1" platform on a second TV in my house for the last couple of weeks. X1, which was recently announced at the Cable Show, is the company's new state-of-the-art set-top box, built by Pace, that delivers video via traditional "QAM" technology along with apps and other content via web-standard IP technology. The latter allows X1 to create a richer, more web-like user experience.

X1's biggest leap forward vs. the traditional Comcast digital set-top (which I still have on my main TV) is its speed and responsiveness. X1 is amazingly fast, unlike any other pay-TV set-top I've ever used, and easily on a par - or better - than any web site or iPad/mobile app I've recently used (it actually feels faster than many web sites I visit given their increasingly bloated pages). X1 also blows away my Samsung connected Blu-ray player's abysmally slow performance.

X1 speed shines in a few obvious ways - when doing searches, when changing channels and when switching between functions. Just like Google, when searching in X1, it immediately begins auto-filling suggested results after the first letter's entry, refining the results as additional letters are added. After selecting a result, X1 quickly takes you to that program's main page where there's cover art, summary info, and options to record via X1's TiVo-like DVR capability, share via Facebook and Twitter, get info about cast and crew, and see an episode guide where you can select from among those available.

Pursuing any of these options is nearly instantaneous, allowing you to go from search to watching in just seconds. One nice feature with search is that if a program is found on both an SD and HD channel, X1 will automatically tune to the HD channel.

X1 also fixes a widespread nit common in digital set-tops, which is the annoying delay when changing channels. With X1, changing channels is a snap and you can surf at lightning speed. Last but not least, X1 moves back and forth between functions seamlessly. Using the main "Xfinity" button allows quick movement between the guide, DVR, on demand options, available apps, search and settings without a hitch. In all of my interactions, X1 never hiccupped, stalled out, needed to be re-started, etc.

Speaking of the guide, this will no doubt be the most noticeable UI enhancement for Comcast subscribers, especially heavy on demand users. The guide has of course long been a sore spot, increasingly so as touch-based swiping content discovery on iPads and smartphones has become commonplace. X1's guide still requires keypad entry via the remote (an iPhone app is available, with iPad soon), but once again, because of the responsiveness, it didn't feel cumbersome (and because the remote is radio-based, not IR, you no longer need to point the remote at the set-top's bullseye).

On-screen fonts and graphics set against a cool gray background feel like any contemporary web experience. And the number of buttons on the remote control itself seem to have been pared back to only the most essential, creating a sleeker-looking device (albeit not one that an Apple logo would ever be found on).

All of this makes the X1 a big step forward from the standpoint of enjoying Comcast's TV service. But while the inclusion of IP technology in X1 gives Comcast the opportunity to incorporate web experiences, this is still mainly untapped potential. Yes, X1 allows you to connect your Facebook, Twitter and Pandora accounts, all of which are handy, and introduces weather, sports and traffic apps all of which are functional, but are primitive compared to what's available online.

Rather, X1 provides a glimpse of how the best of the web could someday be integrated into the set-top user experience, though Comcast has yet to really capitalize on it. For example, integrating with IMDb to allow a robust cast and crew search experience would be a solid enhancement over X1's relatively thin selection of summary information about just the main 4-5 actors in a movie or TV show. No doubt Comcast is well aware of the wealth of online resources and apps and has on its roadmap plans to enhance X1 selectively with them.

Another whole area of the web that X1 doesn't yet touch is online video. While it's understandable that Comcast hasn't integrated Netflix, Amazon, VUDU and others that might be considered direct competitors with Comcast's own video services, X1's most obvious omission is access to YouTube, which has become a standard feature of most connected devices. Being able to browse YouTube with X1's strong UI would be a solid addition, as would access to other popular online video destinations that Roku, for example, has aggressively incorporated. Enabling online video alternatives would allow Comcast to box out (sorry for the pun) emerging connected devices from getting a foothold in the digital living room.

Nevertheless, X1 addresses the most pressing issue Comcast faced: upgrading the user experience for the core TV service to make it more competitive with today's online/mobile experiences. In this respect, X1 is a clear success. If Comcast enhances X1 further with more web content and apps going forward, it will become even more appealing.

Note: At the recent Cable Show, I discussed X1 with Matt Strauss, Comcast's SVP of Digital and Emerging Platforms: